Known lighting systems comprise a power supply like a mains power supply, lamps like incandescent bulbs, and a switch electrically connected between the power supply and the lamps, wherein the switch is adapted such that it can be operated in an ON state and in an OFF state. In the ON state the power supplied by the power supply is provided to the lamps and in the OFF state the power is not provided to the lamps. In such a lighting system a lamp, which only provides the function of emitting light and no further functions requiring electrical power, may be replaced by another lamp, which provides the light emission function and also an additional function like a sensing function that should be active also if light is not emitted. If after this replacement the switch is in its OFF state, not only the light emission function of the new lamp is switched off, but also the additional function which should be still active. The lighting system does therefore not allow the new lamp to provide its full functionality.